Communication Device, Control Method, and Non-Transitory Computer-Readable Storage Medium

This application is a Continuation of International Patent Application No. PCT/JP2024/037124, filed October 18, 2024, which claims the benefit of Japanese Patent Application No. 2023-185970, filed October 30, 2023, both of which are hereby incorporated by reference herein in their entirety.

The present invention relates to communication devices that perform wireless communication, control methods for communication devices, and non-transitory computer-readable storage media.

The IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known as a principal communication standard for WLAN (wireless local area network). The IEEE 802.11 standard series includes standards such as IEEE 802.11a, b, g, n, ac, and ax.

In the IEEE 802.11ax standard described in Japanese Patent Laid-Open No. 2018-50133, it is disclosed that wireless communication is executed based on OFDMA (orthogonal frequency-division multiple access). In the IEEE 802.11ax standard, OFDMA-based wireless communication is executed so that high peak throughput is achieved. Furthermore, a power-saving technology called TWT (Target Wake Time) is introduced in the IEEE 802.11ax standard. In the IEEE 802.11ax standard, an interval between a doze state in which frame exchange is not performed between an AP (access point) and an STA (station) and an awake state in which the frame exchange is performed is negotiated in accordance with the TWT, so that the AP can control the timing for performing communication with each STA. Accordingly, the duration of the awake state in a time during which communication is not performed is reduced, so that the STA can reduce power consumption.

Furthermore, the IEEE 802.11be standard, which is a successor to the IEEE 802.11ax standard, is under standardization. As a new feature of the IEEE 802.11be standard, a function called multi-link communication is being considered, which involves an AP and an STA performing communication by establishing multiple parallel links via multiple different frequency channels. For example, Japanese Patent Laid-Open No. 2021-103805 describes a mechanism for establishing multiple links for multi-link communication. Furthermore, in the IEEE 802.11be standard, low-latency communication using the aforementioned TWT is being considered.

In the IEEE 802.11be standard, R-TWT (Restricted TWT) is being considered.

R-TWT involves setting, within a network (BSS) called SP (Service Period), a period in which only predetermined terminals can perform communication within the network, so that only a predetermined terminal that has been designated transitions to the awake state (communicable state) and can perform communication in the period. By providing the SP in this manner, a terminal permitted to perform communication in the SP can have exclusive access rights to a communication channel. In contrast, a terminal not permitted to perform communication in the SP transitions to, for example, the doze state (non-communicable state) in the period, thereby saving energy.

However, the schedule of the SP is set for each network, and the SP schedule is not shared with a different network (OBSS). Therefore, a terminal that is not aware of the SP schedule of the different network may conceivably execute communication during the SP in the different network. Thus, communication of a terminal permitted to perform communication during the SP may possibly be hindered by communication of a terminal not aware of the SP. This may hinder the realization of low-latency communication using the SP.

The present disclosure is directed to a specific mechanism for sharing TWT-related information across different networks.

A communication device according to an aspect of the present invention is a communication device including: a transmitting unit configured to transmit a first frame including a target wake time (TWT) element via a first network, the TWT element including information related to a restricted-target wake time (R-TWT) in a second network different from the first network. The TWT element at least includes a TWT Wake Interval Mantissa field and a Restricted TWT Schedule Info field. The TWT Wake Interval Mantissa field is set to a value of a mantissa of a TWT wake interval of the second network. The Restricted TWT Schedule Info field indicates that the information related to the R-TWT is active, and that the information related to the R-TWT is information of the second network.

Features of the present disclosure will become apparent from the following description of embodiments with reference to the attached drawings.

Embodiments will now be described in detail below with reference to the appended drawings. The following embodiments are not intended to limit the invention according to the claims. Although the embodiments indicate multiple features, not all of these multiple features are necessarily essential for the invention, and the multiple features may be arbitrarily combined. Moreover, in the appended drawings, identical or similar components are given the same reference signs, and redundant descriptions thereof are omitted.

1 FIG. 101 104 103 101 102 106 104 105 101 104 102 103 illustrates an example of a network configuration according to this embodiment. This embodiment is constituted of a networkas a first network and a networkas a second network different from the first network. In this embodiment, an STA MLDoperating as a terminal participates in the networkconstructed by an AP MLDoperating as a base station. An STA MLDoperating as a terminal station participates in the networkconstructed by an AP MLDoperating as a base station. AP MLD is an abbreviation for Access Point Multi-Link Device, and STA MLD is an abbreviation for Station Multi-Link Device. An STA MLD is also called a non-AP MLD. An MLD is a communication device including multiple STAs (or APs). By including multiple STAs, an MLD can simultaneously establish multiple links with a counterpart MLD via different frequency channels. Moreover, multi-link communication can be performed via the multiple established links. The networkis a network identified based on a first BSS (Basic Service Set), and the networkis a network identified based on a second BSS (Basic Service Set). When viewed from a terminal, such as the AP MLDor the STA MLD, belonging to a certain network, another network different from the network to which the terminal belongs may also be referred to as an OBSS (Overlapping Basic Service Set).

102 103 105 106 102 103 105 106 Although the AP MLD, the STA MLD, the AP MLD, and the STA MLDare described as MLDs as an example in this embodiment, these communication devices do not have to be MLDs and may respectively be an AP, an STA, an AP, and an STA.

102 103 105 106 Each communication device (AP MLD, STA MLD, AP MLD, STA MLD) is configured to be capable of executing wireless frame communication compliant with the IEEE 802.11bn standard, which is a successor to the IEEE 802.11be standard that targets a maximum transmission rate of 46.08 Gbps. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. The principal features of the IEEE 802.11bn standard, which is a successor to the IEEE 802.11be standard, are to achieve high-reliability communication, low-latency communication, and improved throughput under congested conditions. Another objective of 802.11bn is to reduce power consumption at an AP. A wireless frame communicating in accordance with the successor standard is also referred to as a UHR (Ultra High Reliability) PPDU. PPDU is an abbreviation for PLCP Protocol Data Unit, and PLCP is an abbreviation for Physical Layer Convergence Protocol.

The name "UHR" is provided for the sake of convenience in view of the objectives to be achieved in the successor standard and the highlight features of the relevant standard, and may be changed to another name once the standardization is completed. With regard to the name IEEE 802.11bn, another name may be similarly given once the standardization is completed. On the other hand, it should be noted that this description and the appended claims are substantially applicable to all successor standards that are successors to the 802.11be standard. Each communication device can communicate in the 2.4 GHz band, the 3.6 GHz band, the 5 GHz band, and the 6 GHz band, as well as millimeter-wave frequency bands including the 45 GHz band and the 60 GHz band. The frequency bands used by each communication device are not limited to the above, and may include a different frequency band, such as a sub-1 GHz band. Moreover, each communication device can communicate by using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, and 640 MHz. The bandwidths used by each communication device are not limited to the above, and may include a different bandwidth, such as 240 MHz or 4 MHz.

Each communication device can realize multiuser (MU, multi-user) communication in which signals of multiple users are multiplexed by executing OFDMA communication compliant with the IEEE 802.11ax/be/bn standards. OFDMA is an abbreviation for Orthogonal Frequency Division Multiple Access. In OFDMA communication, resource units as portions of a divided frequency band are allocated to respective STAs so as not to overlap each other, and carrier waves of the respective STAs are orthogonal to each other. Therefore, an AP can simultaneously communicate with multiple STAs within a prescribed bandwidth. In addition to the IEEE 802.11 series, each communication device may be compliant with other communication standards, such as Bluetooth (registered trademark), NFC, UWB, ZigBee, and MBOA. UWB is an abbreviation for Ultra Wide Band, and MBOA is an abbreviation for Multi Band OFDM Alliance. NFC is an abbreviation for Near Field Communication. UWB includes wireless USB, wireless 1394, and WiNET. Furthermore, each communication device may also be compliant with a wired communication standard, such as a wired LAN.

102 105 103 106 Specific examples of the AP MLDand the AP MLDinclude a wireless LAN router and a personal computer (PC) but are not limited thereto so long as they are communication devices operable as access points (APs). Each AP MLD may be an information processing device, such as a wireless chip, capable of executing wireless communication compliant with the IEEE802.11bn standard. Specific examples of the STA MLDand the STA MLDinclude a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, a headset, a network camera, a printer, a projector, and smartglasses, but are not limited thereto. Each STA MLD may be an information processing device, such as a wireless chip, capable of executing wireless communication compliant with the IEEE802.11bn standard.

101 104 Although the networkand the network, each constituted of a single AP MLD and a single STA MLD, are configured adjacent to each other as an example of a network configuration according to this embodiment, the number of networks, the number of APs, and the number of STAs are not limited to the above. There may be included multiple networks, multiple APs, and multiple STAs.

2 FIG. 201 202 203 204 205 206 207 illustrates an example of a hardware configuration of each communication device. Each communication device has a storage unit, a control unit, a functional unit, an input unit, an output unit, a communication unit, and an antenna.

201 201 The storage unitis constituted of both or one of a ROM and a RAM, and stores programs for performing various types of operation, to be described later, and various types of information, such as communication parameters for wireless communication. RAM is an abbreviation for Random Access Memory, and ROM is an abbreviation for Read Only Memory. Other than a memory, such as a ROM and a RAM, a storage medium including a nonvolatile storage device, such as a hard disk or an SSD (solid state drive), may be used as the storage unit.

202 202 201 202 201 The control unitis constituted of, for example, a processor, such as a CPU or an MPU, an ASIC (application-specific integrated circuit), a DSP (digital signal processor), or an FPGA (field programmable gate array). CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. The control unitexecutes a program stored in the storage unitand controls the entire device by causing a hardware circuit, such as the ASIC, to operate. The control unitmay control the entire device in cooperation with a program and an OS (Operating System) stored in the storage unit.

202 203 203 203 203 203 203 201 206 102 Furthermore, the control unitcontrols the functional unitto execute a predetermined process, such as imaging, printing, or projecting. The functional unitis hardware used by the device for executing the predetermined process. For example, if the communication device is a digital still camera or a camera-equipped smartphone, the functional unitis an imaging unit that performs an imaging process for capturing a surrounding image via a camera unit (not shown) included in the communication device. For example, if the communication device is a printer, the functional unitis a print unit that performs a printing process on a sheet, such as paper, based on print data obtained by wireless communication from an external source. For example, if the communication device is a projector or smartglasses, the functional unitis a projecting unit that performs a projecting process for image data or video data obtained by wireless communication from an external source. In the case of smartglasses, the projection surface is, for example, an end user's retina. The data to be processed by the functional unitmay be data stored in the storage unitor may be data communicated with another AP or STA via the communication unit, to be described later. Furthermore, a communication device, such as an AP, can provide a network storage function, such as NAS (Network Attached Storage). This function is provided as a web service, such as a network storage service, to another communication device. For example, a communication device, such as an STA, connects to a network storage service provided by an AP MLD or the like by using a protocol, such as SMB, FTP, or WebDAV. Then, the communication device, such as an STA, uploads a file to the storage service or downloads a file from within the storage. The data communication involving the uploading and the downloading is achieved by communicating a UHR PPDU between devices.

204 205 205 204 205 205 204 The input unitreceives various types of operations from a user. The output unitperforms various types of outputs to the user. An output from the output unitincludes at least one of display on a screen, audio output from a loudspeaker, and vibration output. Both the input unitand the output unitmay be realized with a single module, as in a touchscreen. The output unitfunctions as a display unit for presenting information to the user. The input unitfunctions as a reception unit for receiving a user operation.

206 206 207 207 The communication unitperforms control of wireless communication compliant with the IEEE 802.11 standard series, as well as control of IP communication. In this embodiment, the communication unitcan execute communication control for transmitting and receiving a UHR PPDU, which is a wireless frame of the UHR standard, as well as a PPDU compliant with standards preceding the UHR standard, by operating in cooperation with the antenna. The antennais, for example, an antenna capable of transmitting and receiving signals in at least one of frequency bands including a sub-GHz band, 2.4 GHz band, 5 GHz band, 6 GHz band, and millimeter-wave band.

206 If the communication device is compliant with, for example, the NFC standard, the Bluetooth standard, and/or the wired communication standard mentioned above, the communication unitmay be configured to perform control of wireless communication and/or wired communication compliant with these communication standards.

3 FIG. 201 202 202 is a block diagram illustrating an example of a functional configuration of each communication device according to this embodiment. In this embodiment, each functional block is stored as a program in the storage unit, and the function thereof is implemented as a result of the control unitexecuting the program. By executing the program, the control unitcontrols each hardware unit and calculates and processes information, thereby implementing the corresponding function. Some or all of the functional blocks may be implemented in hardware. In this case, some or all of the functional blocks are constituted by, for example, an ASIC (application-specific integrated circuit).

301 302 303 304 305 In this embodiment, each communication device includes a TWT information acquisition unit, a frame generating unit, a frame transmitting-receiving unit, a multi-link control unit, and a UI control unit.

301 The TWT information acquisition unitacquires TWT information, set in a different network, from, for example, a management frame, such as a beacon frame, a probe response frame, or an association response frame, from the different network.

302 301 The frame generating unitgenerates a wireless frame to be transmitted via a frame transmitting-receiving unit, to be described later. In this embodiment, based on the TWT information of the different network acquired by the TWT information acquisition unit, a frame for sharing the TWT information with another communication device is generated.

303 303 302 The frame transmitting-receiving unitincludes an antenna and circuit used for transmitting and receiving a wireless frame (or a signal) to and from another wireless communication device, and also includes a program for controlling the antenna and circuit. In accordance with the IEEE 802.11 standard series, the frame transmitting-receiving unitexecutes communication control of a wireless LAN based on the frame generated by the frame generating unit.

304 The multi-link control unitexecutes control of link-establishment-related processes, including a link establishing process for establishing at least one link to be used in wireless communication with a counterpart MLD, a communication starting process, a process for adding or deleting a link after the link establishment, and a communication terminating process for deleting all links. The link establishing process is mainly constituted of an authentication process, an association process, and a 4-way-hand-shake (4WHS) process.

305 304 305 304 305 305 The UI control unitis constituted of user-interface-related hardware, such as a touchscreen or button for receiving an operation from the user, and a program for controlling the hardware. For example, the multi-link control unitreceives an operation from the user via the UI control unitso as to select a counterpart device to which the communication device is connected. Furthermore, the multi-link control unitreceives an operation from the user via the UI control unitso as to perform a process for selecting or setting an STA that is included in each communication device and that is used by the communication device when establishing a link. The UI control unitmay further have a function for indicating, to the user, information about audio output or the like.

Next, TWT information will be described. In this embodiment, target wake time (TWT) information at least includes information related to a service period (SP). However, the TWT information is not limited to this and may further include other TWT-related information. Examples of information that may be included may be related to a traffic identifier (TID) indicating the type of data transmittable in the SP and a TWT group indicating a group of multiple STAs sharing a common SP.

The SP is a period in which an AP and an STA perform adjustment and setting processes in a network and in which the STA is in an awake state (communicable state). The STA is normally in a doze state (non-communicable state) outside the SP but is not limited thereto, and may be configured to perform communication outside the SP. In the SP, the STA transitions to the awake state to transmit and receive a frame. In contrast, when the STA is outside the SP, the STA can transition to the doze state to save power. The TWT information is not limited to the above and may include information included in TWT parameter information, to be described later. Examples of SP-related information include information related to the start timing of the SP, information related to duration from the start to the end of the SP, and information related to an interval between start timings of SPs.

102 103 101 Next, a flowchart of how TWT information is set in the AP MLDand the STA MLDof the networkwill be described.

4 FIG. 102 103 illustrates an example of the flowchart where the AP MLDreceives a TWT request from the STA MLDand sets the TWT information by transmitting a TWT response in response to the TWT request.

4 FIG. 103 102 103 First, the flowchart shown instarts when the STA MLDsets or updates the TWT information. The following description relates to how the TWT information is set during initial link setup between the AP MLDand the STA MLDin this embodiment.

401 102 206 103 In step S, the AP MLDreceives, via the communication unit, an association request frame including a TWT request transmitted by the STA MLD. A TWT request is information indicating that an STA MLD has requested an AP MLD to set TWT information. The TWT request includes, for example, TWT information, such as information indicating whether or not there is TWT support of an STA serving as a transmission source, and information related to an AID (Association Identifier), an SP start timing, duration from the start to the end of the SP, and a cycle and an interval of the SP.

402 102 103 206 401 102 102 102 In step S, the AP MLDtransmits an association response frame including a TWT response to the STA MLDvia the communication unit. A TWT response is information indicating approval to set, as TWT information, the information related to the start time and end time of the SP and the cycle of the SP in the TWT request received in step S. For example, the AP MLDmay be configured to indicate the approval by including a value equal to the TWT request in the TWT response. If the AP MLDdoes not approve the received TWT request, the AP MLDmay be configured to indicate a value different from the TWT request in the TWT response.

403 102 103 102 In step S, a TWT-information setting process and a link establishment process are performed in the AP MLDand the STA MLDbased on the TWT response transmitted by the AP MLD.

102 103 102 404 105 102 103 After the TWT information is set in the AP MLDand the STA MLD, the AP MLDperiodically transmits a beacon frame including the set TWT information (step S). Accordingly, the AP MLDcan receive and acquire the TWT information with respect to the AP MLDand the STA MLD.

102 103 4 FIG. Although an example of the flow of how the TWT information is set during initial link setup between the AP MLDand the STA MLDis described in, the flow is not limited to this. The flow may start based on the STA MLD 103 transmitting a TWT request after the link setup.

103 106 Furthermore, although the flow described above relates to how the TWT information is set in the AP MLD 102 and the STA MLDin this embodiment, the TWT-information setting process and the link establishment process may be performed in the AP MLD 105 and the STA MLDin accordance with a similar flow.

Before proceeding to the description of the flow of a TWT-information sharing process, an element including a wireless frame to be used when sharing the TWT information used in the TWT-information sharing process will be described.

5 FIG. illustrates an example of a frame format of a reduced neighbor report element according to this embodiment. In this embodiment, TWT information of another network is shared with a network constructed by or connected to the own device by using the reduced neighbor report element. In the following description of each field including the reduced neighbor report element, only the name of the field will be used, and the description of the field will be omitted.

5 FIG. 501 502 503 501 502 503 503 503 The reduced neighbor report element shown inincludes an Element ID, a Length, and Neighbor AP Information Fields. The Element IDis an identifier for identifying an information element and, in this embodiment, includes an identifier indicating the reduced neighbor report element. The Lengthis a field indicating a data length of the element and, in this embodiment, includes information indicating a data length of the Neighbor AP Information Fields. The Neighbor AP Information Fieldsindicate information about a different network and, in this embodiment, include TWT information about the different network. Information included in the Neighbor AP Information Fieldswill be described later.

5 FIG. 501 501 502 503 502 501 Each communication device sequentially generates the reduced neighbor report element shown infrom the Element IDand transmits the generated reduced neighbor report element to another communication device. In this case, each communication device performs the transmission after generating all fields within the element. In detail, each communication device performs the transmission to another communication device after generating all of the Element ID, the Length, and the Neighbor AP Information Fields. Alternatively, each AP MLD may perform the transmission concurrently with the generation of the fields. In detail, for example, each communication device may transmit the Lengthconcurrently with the transmission of the generated Element ID.

5 FIG. Each communication device performs the transmission by including the reduced neighbor report element shown inin a MAC (Medium Access Control) frame such as a beacon frame or a probe response frame. Moreover, in addition to such a MAC frame, each communication device can add the element to a MAC frame such as an association response frame or a re-association response frame.

503 504 505 506 507 504 507 507 507 505 505 506 The Neighbor AP Information Fieldsinclude one or more pieces of neighbor AP information. Each piece of neighbor AP information includes a TBTT Information Header, an Operating Class, a Channel Number, and a TBTT Information Set. An AP indicated in each piece of neighbor AP information may also be referred to as a reported AP. TBTT is an abbreviation for Target Beacon Transmission Time. The TBTT Information Headerincludes information indicating a data length of the TBTT Information Setand information indicating the number of TBTT information fields included in the TBTT Information Set. The number of TBTT information fields is indicated as a value obtained by subtracting 1 from the actual number included in the TBTT Information Set. The Operating Classindicates a channel start frequency. A primary channel of the reported AP is indicated based on information indicated by the Operating Classand the Channel Number.

507 507 503 505 506 The TBTT Information Setincludes one or more pieces of TBTT information. Information included in each piece of TBTT information included in the TBTT Information Setwill be described later. By including multiple pieces of neighbor AP information, the Neighbor AP Information Fieldscan include information related to other multiple APs. A communication device that has received the reduced neighbor report element can identify the primary channel in accordance with the Operating Classand the Channel Number, thereby performing communication control more efficiently.

507 508 509 510 511 512 513 514 508 510 511 509 512 513 514 The TBTT Information Setincludes one or more pieces of TBTT information. Each piece of TBTT information includes a Neighbor AP TBTT Offset, a BSSID, a Short SSID, BSS Parameters, a 20MHz PSD, a MLD Parameters, and TWT Information. The Neighbor AP TBTT Offsetindicates an offset in a time unit (TU) from a previous TBTT to a subsequent TBTT of the reported AP. The BSSID 509 indicates a basic service set identifier (BSSID) of the reported AP. The Short SSIDindicates a 32-bit value calculated from a service set identifier (SSID) of the network constructed by the reported AP. The BSS Parametersindicate various types of information related to the reported AP indicated by the BSSID. The 20MHz PSDis information indicating maximum transmission power and indicates, for example, maximum transmission power corresponding to a 20-MHz primary channel of the reported AP. The MLD Parametersinclude information related to an AP MLD to which the reported AP belongs, and includes, for example, an AP MLD ID as an identifier for an AP MLD and a link ID as an identifier for the link of the reported AP within the AP MLD. The TWT Informationis a field including the TWT information of the reported AP and is used for sharing by including TWT information of another network in the element.

514 515 516 515 516 516 517 518 519 520 521 522 517 518 519 520 521 522 The TWT Informationincludes Controland TWT Parameter Information. The Controlis information related to information included in the TWT Parameter Information, and includes, for example, information indicating whether the TWT information is a broadcast TWT, an individual TWT, or TWT information indicating the TBTT interval. A broadcast TWT is a TWT in which TWT information is set between an AP and multiple STAs. An individual TWT is a TWT in which TWT information is set between an AP and an STA in a one-to-one fashion. The TWT Parameter Informationincludes a Request Type, a Target Wake Time, Nominal Minimum TWT Wake Duration, a TWT Wake Interval Mantissa, Broadcast TWT Info, and Restricted TWT Traffic Info. The Request Typeincludes, for example, a TWT flow identifier for identifying the flow of TWT controlled based on TWT information included the TWT information. The Target Wake Timeis information indicating a time to a subsequent SP, and includes a positive integer corresponding to a timing synchronization function (TSF) time that requests release of the doze state of an STA. The Nominal Minimum TWT Wake Durationis information indicating expected duration of time from the start to the end of the SP, and includes information indicating an expected minimum time that an STA needs to be in the awake state in order for the STA to complete exchange of wireless frames after being released from the doze state. The TWT Wake Interval Mantissais information indicating an interval between start timings of SPs, and includes information indicating a mantissa value of a value indicating an interval at which the doze state of an STA is released. Information included in the Broadcast TWT Infowill be described later. The Restricted TWT Traffic Infodesignates, in a bitmap format, a traffic identifier (TID) as a specific wireless frame for communication in a downlink (DL) direction and an uplink (UL) direction.

521 523 524 525 526 523 522 524 525 526 The Broadcast TWT Infoincludes Restricted TWT Traffic Info Present, Restricted TWT Schedule Info, a Broadcast TWT ID, and Broadcast TWT Persistence. The Restricted TWT Traffic Info Presentincludes information indicating whether or not the Restricted TWT Traffic Infois included. The Restricted TWT Schedule Infowill be described later. The Broadcast TWT IDstores information for identifying TWT information of a broadcast TWT set by the reported AP. The Broadcast TWT Persistencestores information indicating the number of TBTTs within an SP indicated in the TWT information.

524 524 6 FIG. 6 FIG. The Restricted TWT Schedule Infowill now be described with reference to.is a diagram for explaining a value included in the Restricted TWT Schedule Infoand the meaning indicated by the value. Values of 0 to 3 are each used when an AP provides a notification about a TWT schedule to an STA within the own BSS. The value of 0 indicates that the TWT is in the idle state, whereas the values of 1 and 3 each indicate that the TWT schedule is active. The value of 2 indicates that the schedule is active, but that the likelihood of allowing new participation is low. Values of 4 and 5 each mean that the TWT information indicates a TWT schedule of another network (OBSS).

524 524 If the Restricted TWT Schedule Infoincludes the value of 4, the TWT information is TWT information of another network, and the TWT schedule based on the relevant TWT information is in the active state in another BSS. If the fieldincludes the value of 5, the TWT information is TWT information of another network, and the TWT schedule based on the relevant TWT information is in the idle state in another BSS.

7 FIG. 105 101 106 105 101 101 102 105 101 106 104 202 201 105 105 102 The following description with reference torelates to an example of a flowchart of a process in which the AP MLDshares the TWT information of the networkwith the STA MLDby using the aforementioned reduced neighbor report element. In this embodiment, the AP MLDacquires the TWT information of the networkfrom a wireless frame including the TWT information of the networktransmitted by the AP MLD. Then, the AP MLDshares the acquired TWT information of the networkwith the STA MLDof the network. This flowchart indicates a process executed as a result of the control unitreading and executing a computer program stored in the storage unit. For example, this flowchart starts immediately after transmission of a beacon frame regularly transmitted by the AP MLD. This flowchart may start when the AP MLDreceives a wireless frame, such as a beacon frame, a probe response frame, or an association response frame, from the AP MLDconstituting a different network. This flowchart selectively illustrates a process related to sharing of TWT information of an OBSS with an STA of a BSS.

701 105 303 102 102 404 702 701 102 First, in step S, the AP MLDreceives, via the frame transmitting-receiving unit, a wireless frame transmitted by the AP MLD(e.g., the beacon frame transmitted by the AP MLDin step S). If TWT information is included in the wireless frame, the process proceeds to step S. If TWT information is not included, the process ends. The wireless frame received in step Sis a MAC frame transmitted by the AP MLDand assumed to be a management frame, such as a beacon frame, a probe response frame, or an association response frame, but is not limited thereto. For example, a control frame, an action frame, or the like is also possible.

702 301 105 101 701 Subsequently, in step S, the TWT information acquisition unitof the AP MLDacquires the TWT information of the networkfrom the wireless frame including the TWT information received in step S.

703 105 105 105 703 703 704 703 703 701 In step S, the AP MLDdetermines whether or not a predetermined period has elapsed from the start of this flow. The predetermined period in this embodiment is a transmission interval of the beacon frame transmitted by the AP MLD. In other words, the AP MLDaccording to this embodiment determines whether the predetermined period (e.g., 100 TU) has elapsed from the transmission of a previous beacon frame. If it is determined in step Sthat the predetermined period has elapsed (Yes in step S), the process proceeds to step S. If it is determined in step Sthat the predetermined period has not elapsed (No in step S), the process proceeds to step S.

704 704 704 705 704 701 Then, in step S, it is determined whether TWT information of a different BSS is acquired within the predetermined period. If it is determined in step Sthat TWT information of a different BSS is acquired within the predetermined period (Yes in step S), the process proceeds to step S. If it is determined that TWT information of a different BSS is not acquired within the predetermined period (No in step S), the process proceeds to step S.

705 105 101 702 106 303 105 705 101 104 105 105 701 703 701 703 106 303 705 507 705 105 706 706 105 701 105 In step S, the AP MLDstores the TWT information of the networkacquired in step Sinto the aforementioned reduced neighbor report element, and transmits the wireless frame including the element to the STA MLDvia the frame transmitting-receiving unit. In the element, a restricted TWT schedule info subfield is set to 4. The wireless frame transmitted by the AP MLDin step Sis a MAC frame assumed to be a management frame, such as a beacon frame, a probe response frame, or an association response frame, but is not limited thereto. For example, a control frame, an action frame, or the like is also possible. This embodiment relates to an example where the TWT information of the networkalone is included as TWT information of a different network, but is not limited thereto. An assumed example is a case where multiple networks different from the networksurround the AP MLDand TWT information of multiple different BSSs is received until the predetermined period elapses. The TWT-information sharing process in that case will be simply described by using the above-described flow. First, the AP MLDreceives a wireless frame including TWT information of a first different BSS in step S. Then, the TWT information of the first BSS is acquired from the received wireless frame. Subsequently, a wireless frame including TWT information of a second different BSS is received before the predetermined period elapses (No in step S, and step S). Then, the TWT information of the second BSS is acquired from the received wireless frame. After the predetermined period elapses (Yes in step S), the acquired TWT information of the first BSS and the acquired TWT information of the second BSS are stored into the reduced neighbor report element, and a wireless frame including the element is transmitted to the STA MLDvia the frame transmitting-receiving unit(step S). When TWT information of multiple networks is received within the predetermined period in this manner, the TWT information of the multiple networks is shared at once in step S. When the wireless frame including the TWT information is transmitted in step S, the AP MLDcauses the process to proceed to step S. In step S, the AP MLDdetermines whether to stop the network. If it is determined that the network is to be stopped, a network providing process is terminated, and the series of processes is terminated. On the other hand, if it is determined that the network is not to be stopped, the process proceeds to step S, and a series of notification control is performed. In detail, the AP MLDmay determine to stop the network upon reception of a shutdown operation or power off operation (not shown).

105 101 102 106 518 519 520 703 518 106 519 106 520 106 The AP MLDstores the TWT information of the networkreceived from the AP MLDinto the aforementioned reduced neighbor report element and transmits the reduced neighbor report element to the STA MLDin this manner, so that TWT-related information of a different network can be shared with the network to which the own device belongs. The AP MLD 105 may be configured to transmit, as the aforementioned TWT information, information related to at least the Target Wake Time, the Nominal Minimum TWT Wake Duration, and the TWT Wake Interval Mantissain step S. These pieces of information are information related to an SP start timing in another network, information related to SP duration, and information related to an interval between start timings of SPs, respectively. Therefore, by recognizing information included in the Target Wake Time, the STA MLDcan recognize the start timing of a subsequent SP of another network. By recognizing information included in the Nominal Minimum TWT Wake Duration, the STA MLDcan recognize the SP duration of another network. By recognizing information included in the TWT Wake Interval Mantissa, the STA MLDcan recognize the interval between the start timings of SPs of another network.

105 106 An STA connected to the AP MLDand represented by the STA MLDor the like performs transmission suppression control so as not to perform its own data transmission process during the SP of the aforementioned another network that is recognized.

106 101 Accordingly, the STA MLDcan ascertain the SP start timing and duration of the network, and can suppress transmission in the SP of the aforementioned another network that is ascertained. Consequently, interference of communication in the SP of the aforementioned another network can be prevented.

7 FIG. In the above-described control in, the transmission interval of a beacon frame is used as an example of a period for collecting the TWT of the OBSS, and an STA of the BSS is notified of the TWT information of the OBSS received during that period. However, the control is not limited to this. For example, the AP MLD 105 may be configured to manage TWT information transmitted by an AP of the OBSS in association with final acquisition duration thereof, and provide a notification about the TWT information of the OBSS acquired within a predetermined reference time (e.g., within one minute) to an STA of the BSS.

105 101 106 102 103 101 105 101 106 4 FIG. 7 FIG. In the first embodiment, the AP MLDshares the TWT information of the networkwith the STA MLDby using the reduced neighbor report element. In the second embodiment, an example where a neighbor report element is used in place of the reduced neighbor report element will be described. Since a hardware configuration and functional configuration of each communication device according to this embodiment are similar to those in the first embodiment, descriptions thereof will be omitted. Since the TWT-information setting process in the AP MLDand the STA MLDin the networkdescribed with reference toand the process described with reference toin which the AP MLDshares the TWT information of the networkwith the STA MLDare also similar to those in the first embodiment, descriptions thereof will be omitted.

8 FIG. 105 702 106 303 The neighbor report element according to this embodiment will now be described with reference to. The AP MLDstores the TWT information of the different BSS acquired in step Sdescribed above into the element, and transmits a wireless frame including the element to the STA MLDvia the frame transmitting-receiving unit. The wireless frame including the element is a MAC frame assumed to be a management frame, such as a beacon frame, a probe response frame, or an association response frame, but is not limited thereto. For example, a control frame, an action frame, or the like is also possible.

8 FIG. 801 802 803 804 805 806 807 808 801 802 803 804 805 806 803 The neighbor report element shown inincludes an Element ID, a Length, a BSSID, BSSID Information, an Operating Class, a Channel Number, a PHY Type, and an Optional Subelement. Since the Element ID, the Length, the BSSID, the BSSID Information, the Operating Class, and the Channel Numbereach include information similar to the corresponding field of the same name described above, descriptions thereof will be omitted. The PHY Type 807 includes a PHY type of an AP indicated by the BSSID.

808 809 810 515 516 The Optional Subelementincludes a Subelement ID, a Length, Control, and TWT Parameter Information.

105 101 106 By using the aforementioned neighbor report element in this manner, the AP MLDcan share the TWT information of the networkwith the STA MLD.

105 101 106 In the third embodiment, the AP MLDshares the TWT information of the networkwith the STA MLDby using a TWT element in place of the aforementioned elements.

102 103 101 105 101 106 4 FIG. 7 FIG. Since a hardware configuration and functional configuration of each communication device according to this embodiment are similar to those in the first embodiment, descriptions thereof will be omitted. Since the TWT-information setting process in the AP MLDand the STA MLDin the networkdescribed with reference toand the process described with reference toin which the AP MLDshares the TWT information of the networkwith the STA MLDare also similar to those in the first embodiment, descriptions thereof will be omitted.

9 FIG. 702 106 303 The TWT element according to this embodiment will now be described with reference to. The AP MLD 105 stores the TWT information of the different BSS acquired in step Sdescribed above into the element, and transmits a wireless frame including the element to the STA MLDvia the frame transmitting-receiving unit. The wireless frame including the element is a MAC frame assumed to be a management frame, such as a beacon frame, a probe response frame, or an association response frame, but is not limited thereto. For example, a control frame, an action frame, or the like is also possible.

9 FIG. 901 902 515 903 The TWT element shown inincludes an Element ID, a Length, Control, and TWT Parameter Information.

903 904 904 903 904 522 904 526 903 In this embodiment, the TWT Parameter Informationincluded in the TWT element further includes a BSSIDin addition to the aforementioned fields. The BSSIDstores information indicating a BSSID of an AP in which the TWT information indicated in the TWT Parameter Informationis set. This embodiment relates to a case where the BSSIDis stored immediately after the Restricted TWT Traffic Info, but is not limited thereto. For example, the BSSIDmay be stored immediately after the Broadcast TWT Persistence, and may at least be stored in the TWT Parameter Informationincluded in the TWT element. Accordingly, an STA becomes capable of identifying which network the TWT information indicated by the TWT element pertains to. Furthermore, even if there are multiple other networks, it becomes possible to identify which network each piece of TWT information pertains to.

105 101 106 Accordingly, by using the aforementioned TWT element, the AP MLDcan share the TWT information of the networkwith the STA MLD.

According to an aspect of the present invention, TWT-related information can be shared across different networks.

Each of the above-described embodiments relates to the flow of how an AP MLD shares TWT information of another network with an STA MLD, but is not limited thereto. For example, if an STA MLD receives and acquires TWT information of another network, the STA MLD may be configured to share the TWT information of the aforementioned another network by using any of the aforementioned elements.

Each of the above embodiments relates to a case where TWT information of another network is shared, but is not limited thereto. Each element may be configured such that only R-TWT-related information is shared.

105 4 FIG. 7 FIG. Furthermore, the flowchart of the AP MLDshown inandmay at least be partially or entirely realized by hardware. If the flowchart is to be realized by hardware, for example, a predetermined compiler may be used to generate a dedicated circuit on an FPGA from a computer program for implementing the respective steps, and this dedicated circuit may be used. FPGA is an abbreviation for Field Programmable Gate Array. Furthermore, a gate array circuit may be formed similarly to the FPGA and may be realized as hardware. Moreover, the flowchart may be realized by an ASIC (application-specific integrated circuit).

The present invention can also be realized by supplying a program that implements at least one feature of the above embodiments to a system or a device via a network or a storage medium and causing at least one processor in a computer of the system or the device to read and execute the program. Moreover, the present invention can also be realized by a circuit (e.g., ASIC) that implements at least one feature.

The present invention is not limited to the above embodiments, and various alterations and modifications are possible so long as they do not depart from the spirit and scope of the invention. Therefore, claims are appended in order to disclose the scope of the invention.

While the present disclosure has been described with reference to embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.